Some of desktop computers, mobile telephone terminals, mobile information terminals, tablet terminals, and other electronic devices used by users use a touch panel as an input device. These electronic devices may be mounted on a cradle (holder). When an electronic device is mounted on a cradle, the electronic device can be connected to it. A cradle can thereby be used to interconnect the main unit of the electronic device and another electronic device with a cable so that data synchronization is maintained between these electronic devices and files are transmitted and received between them. Another usage of the cradle is to charge the main unit. Some cradles have a universal serial bus (USB) port, enabling a keyboard, a modem, or another peripheral device to be connected to a mobile terminal.
Particularly, dominant tablet terminals use a touch panel as an input device. The user holds the main unit of a tablet terminal with one hand and performs a touch operation with the other hand. The tablet terminal is used at least as a display unit, and the touch panel is used as an input device.
A tablet terminal is used to view a moving picture and still images, in which case the tablet terminal is mounted on a cradle and reproduces the moving picture and still images. In other usages as well, the tablet terminal accepts operation commands made by touch operations.
Japanese Laid-open Patent Publication No. 2004-39861 is known as an example of related art.